[Dy2St]Fix func.__self__ problem in FunctionSpec (#50404)

python/paddle/fluid/tests/unittests/dygraph_to_static/test_list.py

@@ -338,8 +338,10 @@ class ListWithCondNet(paddle.nn.Layer):
     def __init__(self):
         super().__init__()
 
+    # Add *args to test function.__self__ in FunctionSpec.
+    # DO NOT remove *args.
     @paddle.jit.to_static
-    def forward(self, x, index):
+    def forward(self, x, index, *args):
         y = paddle.nn.functional.relu(x)
         a = []
 

python/paddle/jit/dy2static/function_spec.py

@@ -54,7 +54,7 @@ class FunctionSpec:
         # parse *args
         self.varargs_name = parse_varargs_name(function)
         if self.varargs_name is not None and isinstance(
-            function.__self__, TranslatedLayer
+            getattr(function, '__self__', None), TranslatedLayer
         ):
             self._arg_names += function.__self__._input_args_names